Abstract

The combination of a top-down and a bottom-up fabrication approach will be a key technology to overcome the minimum size limit of the top-down approach. Gentle cold welding is a promising method to connect nano objects without appreciable damages to the nano device in a bottom-up approach. We developed the gentle cold welding method using the combination of an electrical field and an atomic rearrangement. The formulated process was visualized between gold tips using a transmission electron microscope. The initial connection mechanism was divided into three modes depending on a bias voltage between tips; (1) physical contact, (2) atom extraction, and (3) field evaporation, depending on the electrical fields. All the nano connections grew by the atomic rearrangement driven by gold surface self-diffusion. The grown connections were single crystalline structures. These results suggested that this welding will be a useful method to build up future nano devices and systems.

Received 20 May 2011Accepted 10 October 2011Published online 23 November 2011

Acknowledgments:

The authors would like to express their sincere gratitude to Professor Takuji Takahashi for the useful discussion and encouragement. They also acknowledge the support from the Center of Excellence (COE) in Electronics for Future Generations and the Global COE “Secure-Life Electronics” sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. This work was supported by KAKENHI; the grant-in-aid of Scientific (S) 16 191 004, Specially Promoted Research 21 000 008, and the grant-in-aid for young scientists (B) 23 760 126 sponsored by the Japan Society for the Promotion of Science (JSPS).